How can I get ScrollViewer to work inside a StackPanel?

Question

In the following WPF XAML the ScrollViewer does not work (it displays a scroll bar but you cannot scroll and the contents go off the window to the bottom).

I can change the outer StackPanel to a Grid and it will work.

However, in my application from which I reproduced the following code, I need to have an outer StackPanel. What do I have to do to the StackPanel to make the ScrollViewer show a usable scrollbar? e.g. VerticalAlignment="Stretch" Height="Auto" don't work.

 <StackPanel>         <ScrollViewer>             <StackPanel>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>                 <TextBlock Text="This is a test"/>             </StackPanel>         </ScrollViewer>  </StackPanel> 

Answer 1

This was bugging me for a while too, the trick is to put your stackpanel within a scrollviewer.

Also, you need to ensure that you set the CanContentScroll property of the scroll viewer to True, here's an example:

  <ScrollViewer Grid.Row="1" Margin="299,12,34,54" Name="ScrollViewer1" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" Height="195" CanContentScroll="True">         <StackPanel Name="StackPanel1" OverridesDefaultStyle="False"  Height="193" Width="376" VerticalAlignment="Top" HorizontalAlignment="Left"></StackPanel>   </ScrollViewer> 

Answer 2

You can't without fixing the height of the StackPanel. It's designed to grow indefinitely in one direction. I'd advise using a different Panel. Why do you "need" to have an outer StackPanel?